Method and system for providing a continuous motion sequential lateral solidification for reducing or eliminating artifacts, and a mask for facilitating such artifact reduction/elimination

ABSTRACT

An arrangement, process and mask for implementing single-scan continuous motion sequential lateral solidification of a thin film provided on a sample such that artifacts formed at the edges of the beamlets irradiating the thin film are significantly reduced. According to this invention, the edge areas of the previously irradiated and resolidified areas which likely have artifacts provided therein are overlapped by the subsequent beamlets. In this manner, the edge areas of the previously resolidified irradiated areas and artifacts therein are completely melted throughout their thickness. At least the subsequent beamlets are shaped such that the grains of the previously irradiated and resolidified areas which border the edge areas melted by the subsequent beamlets grow into these resolidifying edges areas so as to substantially reduce or eliminate the artifacts.

FIELD OF THE INVENTION

The present invention relates to a method, system and mask forprocessing a thin-film semiconductor material, and more particularly toforming large-grained, grain-shaped and grain-boundary-locationcontrolled semiconductor thin films from amorphous or polycrystallinethin films on a substrate by continuous motion-scanning the entiresample or at least one portion thereof using a sequential lateralsolidification technique so as to reduce or even eliminate artifacts,e.g., that may be formed in overlapped irradiated, melted andresolidifying regions of a sample or in the portion(s) thereof.

BACKGROUND INFORMATION

In the field of semiconductor processing, a number of techniques havebeen described to convert thin amorphous silicon films intopolycrystalline films. For example, in James Im et al., “Crystalline SiFilms for Integrated Active-Matrix Liquid-Crystal Displays,” 11 MRSBulletin 39 (1996), an overview of conventional excimer laser annealingtechnology is described. In such conventional system, an excimer laserbeam is shaped into a beam having an elongated cross-section which istypically up to 30 cm long and 500 micrometers or greater in width. Theshaped beam is stepped over a sample of amorphous silicon (i.e., bytranslating the sample) to facilitate melting thereof and to effectuatethe formation of grain-shape and grain boundary-controlledpolycrystalline silicon upon the re-solidification of the sample. Suchtechniques has been referred to as sequential lateral solidification(“SLS”) of the melted portions of the sample to effectuate the growth oflonger grain boundaries therein so as to achieve, e.g., uniformity amongother thing.

Various techniques, processes, masks and samples have been previouslydescribed which utilize various SLS techniques, to effectively processthe sample. For example, International Publication No. 02/086954describes a method and system for providing a single-scan, continuousmotion sequential lateral solidification of melted sections of thesample being irradiated by beam pulses. In this publication, anaccelerated sequential lateral solidification of the polycrystallinethin film semiconductors provided on a simple and continuous motiontranslation of the semiconductor film are achieved, without thenecessity of “microtranslating” the thin film, and re-irradiating thepreviously irradiated region in the direction which is the same as thedirection of the initial irradiation of the thin film while the sampleis being continuously translated.

One problem that may arise during SLS processing of a thin film providedon a sample is microstructural artifacts, e.g., grain misalignment. Forexample, these artifacts may be formed in the area of beamlet overlap.Such areas in which artifacts may form may be tail areas of the newestbeamlet(s) irradiating the sample which overlap front or head areas ofthe previously irradiated and resolidified portion of the sample. Theseartifacts may arise because the edge of the beam (e.g., rounded orsquare-shaped), which is reproduced in the molten portion, leads tolateral growth of grains extending in from the edges at angles that areskewed to the desired direction of the lateral growth.

OBJECT AND SUMMARY OF THE INVENTION

An object of the present invention is to provide techniques for forminglarge-grained, grain-shaped and grain-boundary-location controlledpolycrystalline thin film semiconductors using a sequential lateralsolidification (“SLS”) process, and to reduce or eliminate artifacts.

According to the present invention, an arrangement, process and mask areprovided for implementing single-scan continuous motion sequentiallateral solidification of a thin film situated on a sample such thatartifacts are reduced or eliminated. For example, according to thepresent invention artifacts that may be formed at the edges of thebeamlets irradiating the thin film are significantly reduced. Accordingto this invention, the edge areas of the previously irradiated andresolidified areas which likely have artifacts provided therein areoverlapped by the subsequent beamlets. In this manner, the edge areas ofthe previously resolidified irradiated areas and artifacts therein arecompletely melted throughout their thickness. At least the subsequentbeamlets are shaped such that the grains of the previously irradiatedand resolidified areas which border the edge areas melted by thesubsequent beamlets grow into these resolidifying edges areas so as tosubstantially reduce or eliminate the artifacts.

In one exemplary embodiment of the present invention, an arrangement,process and mask can be provided for processing at least one portion ofa thin film sample on a substrate. In particular, an irradiation beamgenerator can be controlled to emit successive irradiation beam pulsesat a predetermined repetition rate. The exemplary mask may receivethereon each of the irradiation beam pulses. Such mask can include abeam pattern which, when the beam pulses irradiate therethrough, definesone or more first beamlets and one or more second beamlets, with each ofthe first and second beamlets having two opposite edge sections and acenter section. The first beamlets can irradiate one or more first areasof the film sample so that the first areas are melted throughout theirthickness.

At least one first section of the first areas irradiated by at least oneparticular beamlet of the first beamlets is allowed to re-solidify andcrystallize thereby having grains grown therein. The first sectionincludes at least one first resolidified area irradiated by the one ofthe edge sections of the particular beamlet, the first resolidified areaincluding artifacts therein. After the one or more first areas areirradiated, the second beamlets irradiate one or more second areas ofthe film sample so that the second areas are melted throughout theirthickness. At least one second section of the second areas irradiated bythe subsequent beamlet is allowed to re-solidify and crystallize therebyhaving grains grown therein. The second section includes at least onesecond resolidified area irradiated by the at least one of the edgesections of the subsequent beamlet which overlaps the artifacts providedin the first resolidified area. In this manner, the artifacts can thusbe substantially reduced or even eliminated upon the resolidification ofthe second section of the second area.

According to another exemplary embodiment of the present invention, theedge sections of each of the first and second beamlets are a frontsection and a rear section. The first resolidified area can beirradiated by the rear section of the particular beamlet, and the secondresolidified area may be irradiated by the front section of thesubsequent beamlet. The rear section of at least one particular beamlethas a width for a substantial length thereof which is smaller than awidth of the center section of the particular beamlet. In addition, thefront section of at least one subsequent beamlet of the second beamletshas a width for a substantial length thereof which is smaller than awidth of the center section of the subsequent beamlet.

In yet another exemplary embodiment of the present invention, the rearsection of the particular beamlet and the front section of thesubsequent beamlet have substantially straight edges in which thestraight edges slope toward one another and away from the center sectionof the respective one of the particular and subsequent beamlets. Also,the rear section of the particular beamlet and the front section of thesubsequent beamlet can have a triangular shape. For example, each of thefront and rear sections has three apexes, and one of the apexes of eachof the front and rear sections points away from the central section of arespective one of the particular and subsequent beamlets. In yet anotherexemplary embodiment, the rear section of the particular beamlet and thefront section of the subsequent beamlet have a trapezoid shape. Thus,the trapezoid-shaped rear section of the particular beamlet may have afirst conceptual side extending for a width of the central section ofthe particular beamlet and a second side provided at an edge of the rearsection away from the central section, with the first side being greaterthan the second side. The trapezoid-shaped front section of thesubsequent beamlet can have a third conceptual side extending for awidth of the central section of the subsequent beamlet, and a fourthside provided at an edge of the front section away from the centralsection. The third side is preferably greater than the fourth side. Inanother embodiment of the present invention, upon the resolidificationof the second section of the second area, at least most of the grainsfrom the resolidified first section of the first area that are adjacentto the second section grow into the solidifying second section in adirection which is approximately perpendicular to a direction ofextension of the solidifying second section.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplary embodiments of the present invention will now be described infurther detail with reference to the accompanying drawings in which:

FIG. 1 shows a diagram of an exemplary embodiment of a system forperforming a single-scan, continuous motion sequential lateralsolidification (“SLS”) according to the present invention which does notrequire a microtranslation of a sample for an effective large graingrowth in a thin film, and effectuates a bi-directional grain growthwithin the irradiated and re-solidified area of the sample;

FIG. 2A shows an enlarged illustration of a first mask utilized by theconventional systems and methods having a rectangular shape, whichfacilitates the single-scan, continuous motion SLS as an intensitypattern generated thereby impinges the thin film on a substrate of thesample, and using which microstructural artifacts may possibly form;

FIG. 2B shows an enlarged view of the resolidified region of the sampleirradiated by one exemplary beamlet shaped by the mask of FIG. 2A whichoverlaps a portion of the previously resolidified region, as well asartifacts formed at the overlapped area;

FIG. 2C show an exemplary sequential stage of the SLS processing of thesample using the mask of FIG. 2A and the grain structures on theresolidified areas of the sample which shows microstructural artifactsprovided in the areas where the previously-irradiated and resolidifiedareas have been overlapped by the newly irradiated and resolidifiedareas;

FIG. 3A shows an enlarged illustration of a second mask having a roundor curved edges that may be utilized by the conventional systems andmethods which facilitates the single-scan, continuous motion SLS, andusing which microstructural artifacts may possibly form;

FIG. 3B shows an enlarged view of the resolidified region of the sampleirradiated by one exemplary beamlet shaped by the mask of FIG. 3A whichoverlaps a portion of the previously resolidified region, as well as theillustration of the artifacts formed at the overlapped area;

FIG. 4A shows an enlarged illustration of a first exemplary embodimentof the mask utilized by the system and method according to the presentinvention having a triangular shape at the edges thereof using whichmicrostructural artifacts may be reduced or eliminated;

FIG. 4B shows an enlarged view of the resolidified region of the sampleirradiated by one exemplary beamlet shaped by the mask of FIG. 4A whichoverlaps a portion of the previously resolidified region, andillustrates the reduction or elimination of the artifacts;

FIG. 4C show an exemplary sequential stage of the SLS processing of thesample using the mask of FIG. 3A and the grain structures on theresolidified areas of the sample which shows the reduction orelimination of the microstructural artifacts provided in the areas wherethe previously-irradiated and resolidified areas have been overlapped bythe newly irradiated and resolidified areas; and

FIG. 5A shows an enlarged illustration of a second exemplary embodimentof the mask utilized by the system and method according to the presentinvention having a tapered shape at the edges thereof using whichmicrostructural artifacts may be reduced or eliminated.

DETAILED DESCRIPTION

Certain systems and methods for providing a single scan, continuousmotion SLS are described in International Publication No. 02/086954 (the. “'954 Publication”), the entire disclosure of which is incorporatedherein by reference. The '954 Publication explicitly describes andillustrates the details of these systems and methods, and theirutilization of microtranslations of a sample, which may have anamorphous silicon thin film provided thereon that can be irradiated byirradiation beam pulses so as to promote the sequential lateralsolidification on the thin film, without the need to microtranslate thesample and/or the beam relative to one another to obtain a desiredlength of the grains contained in the irradiated and re-solidified areasof the sample. Similar to the system described in the '954 Publication,an exemplary embodiment of a system for carrying out the continuousmotion SLS processing of amorphous silicon thin films and reduce oreliminate microstructural artifacts according to the present inventionis illustrated in FIG. 1. The exemplary system includes a Lambda Physikmodel LPX-3151 XeCl pulsed excimer laser 110 emitting an irradiationbeam (e.g., a laser beam), a controllable beam energy density modulator120 for modifying the energy density of the laser beam, a MicroLas twoplate variable attenuator 130, beam steering mirrors 140, 143, 147, 160and 162, beam expanding and collimating lenses 141 and 142, a beamhomogenizer 144, a condenser lens 145, a field lens 148, a projectionmask 150 which may be mounted in a translating stage (not shown), a4x-6x eye piece 161, a controllable shutter 152, a multi-elementobjective lens 163 for focusing an incident radiation beam pulse 164onto a sample 170 having a silicon thin film 52 to be SLS processedmounted on a sample translation stage 180, a granite block optical bench190 supported on a vibration isolation and self-leveling system 191,192, 193 and 194, and a computer 106 (e.g., a general purpose computerexecuting a program or a special-purpose computer) coupled to controlthe pulsed excimer laser 110, the beam energy density modulator 120, thevariable attenuator 130, the shutter 152 and the sample translationstage 180.

The sample translation stage 180 may be controlled by the computer 106to effectuate translations of the sample 40 in the planar X-Y directionsand the Z direction. In this manner, the computer 106 controls therelative position of the sample 40 with respect to the irradiation beampulse 164. The repetition and the energy density of the irradiation beampulse 164 may also be controlled by the computer 106. It should beunderstood by those skilled in the art that instead of the pulsedexcimer laser 110, the irradiation beam pulse can be generated byanother known source of short energy pulses suitable for melting asemiconductor (or silicon) thin film. Such known source can be a pulsedsolid state laser, a chopped continuous wave laser, a pulsed electronbeam and a pulsed ion beam, etc. with appropriate modifications to theradiation beam path from the source 110 to the sample 170. In theexemplary embodiment of the system shown in FIG. 1, while the computer106 controls translations of the sample 170 for carrying out thesingle-scan, continuous motion SLS processing of the thin film accordingto the present invention, the computer 100 may also be adapted tocontrol the translations of the mask 150 and/or the excimer laser 110mounted in an appropriate mask/laser beam translation stage (not shownfor the simplicity of the depiction) to shift the intensity pattern ofthe irradiation beam pulses 164, with respect to the silicon thin film,along a controlled beam path. Another possible way to shift theintensity pattern of the irradiation beam pulse is to have the computer100 control a beam steering mirror. The exemplary system of FIG. 1 maybe used to carry out the single-scan, continuous motion SLS processingof the silicon thin film on the sample 170 in the manner usingconventional masks, as well as those used according to the exemplaryembodiments of the present invention. The details of such processing areset forth in further detail below.

An amorphous silicon thin film sample may be processed into a single orpolycrystalline silicon thin film by generating a plurality of excimerlaser pulses of a predetermined fluence, controllably modulating thefluence of the excimer laser pulses, homogenizing the intensity profileof the laser pulse plane, masking each homogenized laser pulses todefine beamlets, irradiating the amorphous silicon thin film sample withthe beamlets to effect melting of portions thereof that were irradiatedby the beamlets, and controllably and continuously translating thesample 170 with respect to the patterned beamlets. The output of thebeamlets is controllably modulated to thereby process the amorphoussilicon thin film provided on the sample 170 into a single orgrain-shape, grain-boundary-location controlled polycrystalline siliconthin film by the continuous motion sequential translation of the samplerelative to the beamlets, and the irradiation of the sample by thebeamlets of masked irradiation pulses of varying fluence atcorresponding sequential locations thereon. One of the advantages of thesystem, method and mask according to the present invention is that theability to reduce or eliminate the microstructural artifacts that may beformed on the areas on the sample in which edges (e.g., rear edges) ofthe newly irradiated and solidifying region of the sample 170 partiallyoverlap edges (e.g., front edges) of the previously resolidified regionof the sample 170.

FIG. 2A shows an enlarged illustration of a first mask 150 that hasrectangular-shaped slits, as used in conventional continuous motionSLS-type systems and processes. These slits shape the beam being passedtherethrough to produce an intensity pattern that impinges the thin filmprovided on the sample 170, and to be in a shape that is substantiallythe same as the shape of the corresponding slit. In particular, theslits of the mask 150 allow the respective portions of the beam 149 toirradiate therethrough, while other sections of the mask 150 are opaque,and do not allow the portions of the beam 149 to be transmitted throughthese opaque sections. This mask 150 includes a first set ofrectangular-shaped slits 210 situated at an offset from one anotheralong a negative Y-axis, and a second set of rectangular-shaped slits215 are also provided at an offset from one another along a negativeY-axis, but also distanced from the first slits. The positioning of thefirst and second slits with respect to one another is shown anddescribed in further detail in the '954 Publication.

FIG. 2B shows an exemplary illustration of the irradiation of the sample170 by a sample beamlet of the intensity pattern shaped by the mask ofFIG. 2A. In operation, this beamlet is irradiated on the sample so as topartially cover a portion (e.g., a front portion 265) of the previouslyirradiated, melted and resolidified area of the sample with its ownportion (e.g., a tail portion 270). For example, the front portion 265of the previously-resolidified area may have the grains grown in theorientation that is approximately parallel to the direction of thetranslation of the sample 170 and/or the beam pulse 164. Upon theirradiation of the next sequential region by the subsequent beamlet, apart of the front portion 265 is overlapped by the tail portion 270 ofsuch beamlet, so as to completely melt, resolidify and form respectiveportions of the subsequent region 250, including a new front portion 260and the tail portion 270. The grains of the front portion 265 of thepreviously resolidified region extend at angles that are contrary to thedesirable direction of grain growth.

For example, the grains may extend approximately along the relativetranslation direction of the sample, which is unfavorable for processingthe sample according to the continuous motion SLS-techniques. Suchundesired grain growth is shown for the new front portion 260, whichillustrates that that grains grow from the edges of the irradiated andfully melted region 250, such that at least some of the grains extendalong the length of the region 250, thus potentially producingundesirable effects. On the other end, the undesirable grains that existin the portion of the previously resolidified region 265 (extendingapproximately along the length of such region) grow into the tailportion 270 of the newly irradiated, melted and resolidifying region.Accordingly, the tail portion 270 of the resolidifying region 250 mayhave undesirably-oriented grains provided therein.

FIG. 2C illustrates a section of the sample 170 which has been processedby one 610 two 620 and three 630 sequential intensity profiles producedby the mask of 150 of FIG. 2A. The undesired grain growth describedabove with reference to FIG. 2B is shown herein. In addition, thepreviously solidified region 275 (which has the head portion 265 withthe grains extending in an undesired manner) has a bottom region 280with grains that extend into a top portion 285 of a furtherresolidifying region by seeding the resolidifying portions thereof withthe grains of the bottom region 280. This further region is melted bythe beamlet that is produced by the slits (215 and 210) of the mask 150of FIG. 2B. Such further region also includes a respective front portion295 in which undesired grains are grown as described above.

FIG. 3A shows an enlarged illustration of a second mask 150 that hasslits with rounded edges, as used in conventional continuous motionSLS-type systems and processes. It is also possible for the edges tohave a circular shape as well in this mask 150. This mask 150 includes afirst set of round-edge slits 310 situated at an offset from one anotheralong a negative Y-axis, and a second set of round-edge slits 315 arealso provided at an offset from one another along a negative Y-axis, butalso distanced from the first slits. The positioning of the first andsecond slits 310, 315 with respect to one another is substantiallysimilar to that of the first and second slits 210, 215.

FIG. 3B shows an exemplary illustration of the irradiation of the sample170 by a sample beamlet of the intensity pattern shaped by the mask 150of FIG. 3A. In this illustration and similarly to the illustration ofFIG. 2B, the front portion 365 of the previously-resolidified area mayhave the grains grown in the orientation that is approximately parallelto the direction of the translation of the sample 170 and/or the beampulse 164, even though the edges of the resolidifying portions arecurved or rounded. Indeed, the fact that the edges of the slits 310, 315have such shape may promote the undesired grain growth along thedirection of the relative translation of the sample 170. Again, a partof the front portion 365 of this previously resolidified is overlappedby the tail portion 270 of the newly melted and solidifying region 350,and such region 250 also includes a new front portion 260 and the tailportion 370. The grains of the front portion 365 of the previouslyresolidified region extend at angles that are contrary to the desirabledirection of grain growth, and producing the microstructural artifactsin the overlapped portions.

In order to reduce or eliminate artifacts, the exemplary mask, methodand system according to the present invention are described herein. Inparticular, FIG. 4A shows an enlarged illustration of a first exemplaryembodiment of the mask 150 according to the present invention which hasslits with tapered areas on the ends thereof, that can be used withcontinuous motion SLS-type systems and processes according to thepresent invention. In this exemplary embodiment, both ends of each slit412, 413 have triangular-shaped sections which point away from therespective slit. As described above with respect to the masks shown inFIGS. 2A and 2B, these slits shape the beam being passed therethrough toproduce an intensity pattern that impinges the thin film provided on thesample 170, and to be in a shape that is substantially the same as theshape of the corresponding slit. The positioning of the first and secondslits with respect to one another approximately similar to that of thefirst and second slits 210, 215.

FIG. 4B shows an exemplary illustration of the irradiation of the sample170 by a sample beamlet of the intensity pattern shaped by the mask ofFIG. 2A. In operation, this beamlet is irradiated on the sample so as topartially cover a portion (e.g., a front portion 465) of the previouslyirradiated, melted and resolidified area of the sample with its ownportion (e.g., a tail portion 470). The front portion 465 of thepreviously resolidified region is produced by a section of the beamletthat is shaped by a triangular portion 412 of the slit 410. The tailportion 470 of the newly melted and resolidifying region 450 is producedby another section of the beamlet that is shaped by thereverse-triangular portion 413 of the slit 410. For example, the frontportion 465 of the previously-resolidified area may have very few grainsgrown in the orientation that is approximately parallel to the directionof the translation of the sample 170 and/or the beam pulse 164. Indeed,because the portion 465 has a tapered (e.g., triangular) shape as shownin FIG. 4B, most of the grains grown therein, upon its resolidification,would grow in the direction that is approximately perpendicular to thetranslation direction of the sample 170 and/or that of the beam pulse164.

Upon the irradiation of the next sequential region by the subsequentbeamlet, a part of the front portion 465 is overlapped by the tailportion 470 of such beamlet, so as to completely melt, resolidify andform respective portions of the subsequent region 450, including a newfront portion 460 and the tail portion 470. Such overlap by the tailportion 470 of the region 450 melts at least the very end areas of thefront portion 465 of the previously resolidified region. Indeed, theseend areas may contain the undesired grains which undesirably grew in thedirection of the translation of the sample and/or that of the beam pulse164. Thus, the properly oriented grains of the front portion 465 wouldbe the primary grains that seed the resolidifying tail portion 470 ofthe region 450. Therefore, the grains of the resolidifying portion 450at the tail portion 470 thereof which overlaps the front portion 450would be oriented in a desired manner (e.g., oriented perpendicularly tothe direction of translation of the sample 170 and/or of the beam pulse164). Indeed, as shown in FIG. 4B, such grain growth minimizes, andpossibly eliminates the microstructural artifacts that may exist in theoverlapped portions of the resolidified regions.

FIG. 4C illustrates a section of the sample 170 which has been processedby one 710 two 720 and three 730 sequential intensity profiles producedby the mask of 150 of FIG. 4A. The desired &rain growth in theoverlapped portions of the resolidified regions described above withreference to FIG. 4B is shown herein. In addition, the previouslysolidified region 475 (which has the head portion 465 with the grainsextending in a desired manner) has a bottom region 480 with grains thatextend into a top portion 485 of a further resolidifying region byseeding the resolidifying portions thereof with the grains of the bottomregion 480. This further region is melted by the beamlet that isproduced by slits (410 and 415) of the mask 150 of FIG. 4B. Such furtherregion also includes a respective front portion 495 in which theundesired grains are grown as described above. Similarly to thedescription above with reference to FIG. 2C, there is a multiplicity ofthe regions 450 with the orientation of the grains in the overlappingareas. Thus, the exemplary mask, method and system according to thepresent invention provides for the reduction and/or removal ofmicrostructural artifacts in the overlapping portions of theresolidified regions.

FIG. 5A shows an enlarged illustration of another exemplary embodimentof the mask 150 that has slits with tapered cut-off edges for use withthe continuous motion SLS-type systems and processes according to thepresent invention. This mask 150 includes a first set of tapered cut-offslits 510 situated at an offset from one another along a negativeY-axis, and a second set of tapered cut-off slits 515 are also providedat an offset from one another along a negative Y-axis, but alsodistanced from the first slits. The positioning of the first and secondslits 510, 515 with respect to one another is substantially similar tothat of the first and second slits 410, 415.

FIG. 5B shows an exemplary illustration of the irradiation of the sample170 by a sample beamlet of the intensity pattern shaped by the mask 150of FIG. 5A. In this illustration and similarly to the illustration ofFIG. 4B, the front portion 565 is produced by the section of the beamletthat is shaped by a tapered portion 512 of the slit 510. This frontportion 565 of the previously-resolidified area may have the desirablegrains grown in the orientation that is approximately perpendicular tothe direction of the translation of the sample 170 and/or the beam pulse164, and the rear portion 570 that overlaps at least a section of thefront portion 565 is produced by the section of the beamlet that isshaped by a tapered portion 513 of the slit 510. This front portion 565of the previously-resolidified area may have the desirable grains grownin the orientation that is approximately perpendicular to the directionof the translation of the sample 170 and/or the beam pulse 164.Similarly to the description provided above for sequential irradiationof the sample 170 by the mask of FIG. 4A, the sections of the tailportion 470 of the region 550 that may have any undesired grains thereinare overlapped the front portion 465 of the previously resolidifiedregion, and thus the properly oriented grains seed the melted tailportion 570 of the region 550 such that the grains are desirably grownin the direction that is perpendicular to the direction of thetranslation of the sample and/or that of the beam pulse 164. In thismanner, any existent microstructural artifacts provided in theoverlapped portions of the resolidified regions are reduced or eveneliminated.

The foregoing exemplary embodiments merely illustrate the principles ofthe present invention. Various modifications and alterations to thedescribed embodiments will be apparent to those skilled in the art inview of the teachings herein without departing from the scope of theinvention, as defined by the appended claims.

1. A process for processing at least one portion of a thin film sampleon a substrate, the method comprising the steps of: (a) controlling anirradiation beam generator to emit successive irradiation beam pulses ata predetermined repetition rate; (b) masking each of the irradiationbeam pulses to define one or more first beamlets and one or more secondbeamlets, each of the first and second beamlets having two opposite edgesections and a center section; (c) irradiating one or more first areasof the film sample by the first beamlets so that the first areas aremelted throughout their thickness, wherein at least one first section ofthe first areas irradiated by at least one particular beamlet of thefirst beamlets is allowed to re-solidify and crystallize thereby havinggrains grown therein, the at least one first section including at leastone first resolidified area; and (d) after step (c), irradiating one ormore second areas of the film sample by the second beamlets of theirradiation beam pulses so that the second areas are melted throughouttheir thickness, wherein at least one second section of the second areasirradiated by the at least one subsequent beamlet is allowed tore-solidify and crystallize thereby having grains grown therein, the atleast one second section including at least one second resolidified areairradiated by the at least one of the edge sections of the subsequentbeamlet which overlaps the at least one first resolidified area, whereinartifacts are substantially reduced and eliminated upon theresolidification of the at least one second section of the second area.2. The process according to claim 1, wherein the edge sections of eachof the first and second beamlets are a front section and a rear section,wherein the at least one first resolidified area is irradiated by therear section of the particular beamlet, and wherein the at least onesecond resolidified area is irradiated by the front section of thesubsequent beamlet.
 3. The process according to claim 2, wherein therear section of at least one particular beamlet has a width for asubstantial length thereof which is smaller than a width of the centersection of the at least one particular beamlet, and wherein the frontsection of at least one subsequent beamlet of the second beamlets has awidth for a substantial length thereof which is smaller than a width ofthe center section of the subsequent beamlet.
 4. The process accordingto claim 2, wherein the rear section of the particular beamlet and thefront section of the subsequent beamlet have substantially straightedges which slope toward one another and away from the center section ofthe respective one of the particular and subsequent beamlets.
 5. Theprocess according to claim 2, wherein the rear section of the particularbeamlet and the front section of the subsequent beamlet have atriangular shape.
 6. The process according to claim 5, wherein each ofthe front and rear sections has three apexes, and wherein one of theapexes of each of the front and rear sections points away from thecentral section of a respective one of the particular and subsequentbeamlets.
 7. The process according to claim 2, wherein the rear sectionof the particular beamlet and the front section of the subsequentbeamlet have a trapezoid shape.
 8. The process according to claim 7,wherein the trapezoid-shaped rear section of the particular beamlet hasa first conceptual side extending for a width of the central section ofthe particular beamlet, and a second side provided at an edge of therear section away from the central section, the first side being greaterthan the second side.
 9. The process according to claim 7, wherein thetrapezoid-shaped front section of the subsequent beamlet has a thirdconceptual side extending for a width of the central section of thesubsequent beamlet, and a fourth side provided at an edge of the frontsection away from the central section, the third side being greater thanthe fourth side.
 10. The process according to claim 1, wherein, upon theresolidification of the at least one second section of the second area,at least most of the grains from the at least one resolidified firstsection of the first area that are adjacent to the at least one secondsection grow into the at least one solidifying second section in adirection which is approximately perpendicular to a direction ofextension of the at least one solidifying second section.
 11. Anarrangement for processing at least one portion of a thin film sample ona substrate, comprising: a processing system controlling an irradiationbeam generator to emit successive irradiation beam pulses at apredetermined repetition rate; and a mask receiving thereon each of theirradiation beam pulses, the mask including a beam pattern which, whenthe beam pulses irradiate therethrough, defines one or more firstbeamlets and one or more second beamlets, each of the first and secondbeamlets having two opposite edge sections and a center section, whereinthe first beamlets irradiate one or more first areas of the film sampleso that the first areas are melted throughout their thickness, whereinat least one first section of the first areas irradiated by at least oneparticular beamlet of the first beamlets is allowed to re-solidify andcrystallize thereby having grains grown therein, the at least one firstsection including at least one first resolidified area wherein, afterthe one or more first areas are irradiated, the second beamletsirradiate one or more second areas of the film sample so that the secondareas are melted throughout their thickness, wherein at least one secondsection of the second areas irradiated by the at least one subsequentbeamlet is allowed to re-solidify and crystallize thereby having grainsgrown therein, the at least one second section including at least onesecond resolidified area irradiated by the at least one of the edgesections of the subsequent beamlet which overlaps the at least one firstresolidified area, and wherein artifacts are substantially reduced andeliminated upon the resolidification of the at least one second sectionof the second area.
 12. The arrangement according to claim 11, whereinthe edge sections of each of the first and second beamlets are a frontsection and a rear section, wherein the at least one first resolidifiedarea is irradiated by the rear section of the particular beamlet, andwherein the at least one second resolidified area is irradiated by thefront section of the subsequent beamlet.
 13. The arrangement accordingto claim 12, wherein the rear section of at least one particular beamlethas a width for a substantial length thereof which is smaller than awidth of the center section of the at least one particular beamlet, andwherein the front section of at least one subsequent beamlet of thesecond beamlets has a width for a substantial length thereof which issmaller than a width of the center section of the subsequent beamlet.14. The arrangement according to claim 12, wherein the rear section ofthe particular beamlet and the front section of the subsequent beamlethave substantially straight edges which slope toward one another andaway from the center section of the respective one of the particular andsubsequent beamlets.
 15. The arrangement according to claim 12, whereinthe rear section of the particular beamlet and the front section of thesubsequent beamlet have a triangular shape.
 16. The arrangementaccording to claim 15, wherein each of the front and rear sections hasthree apexes, and wherein one of the apexes of each of the front andrear sections points away from the central section of a respective oneof the particular and subsequent beamlets.
 17. The arrangement accordingto claim 12, wherein the rear section of the particular beamlet and thefront section of the subsequent beamlet have a trapezoid shape.
 18. Thearrangement according to claim 17, wherein the trapezoid-shaped rearsection of the particular beamlet has a first conceptual side extendingfor a width of the central section of the particular beamlet, and asecond side provided at an edge of the rear section away from thecentral section, the first side being greater than the second side. 19.The arrangement according to claim 17, wherein the trapezoid-shapedfront section of the subsequent beamlet has a third conceptual sideextending for a width of the central section of the subsequent beamlet,and a fourth side provided at an edge of the front section away from thecentral section, the third side being greater than the fourth side. 20.The arrangement according to claim 11, wherein, upon theresolidification of the at least one second section of the second area,at least most of the grains from the at least one resolidified firstsection of the first area that are adjacent to the at least one secondsection grow into the at least one solidifying second section in adirection which is approximately perpendicular to a direction ofextension of the at least one solidifying second section.
 21. A maskingarrangement utilized for processing at least one portion of a thin filmsample on a substrate, comprising: at least one portion configured toreceive thereon irradiation beam pulses, the at least one portionincluding a front section, a rear section and a center section, whereinwhen the beam pulses irradiate through the front, rear and centersection modified beam pulses are produced which define one or more firstbeamlets and one or more second beamlets, wherein the rear section of atleast one portion has a first width which is smaller than a width of thecenter section of the at least one portion, and wherein the frontsection of at least one portion has a second width which is smaller thanthe width of the center section wherein the width of the center section,the first width and the second width are arranged substantiallyperpendicular to the irradiation beam pulses.